As described by the FAA (Federal Aeronautics Administration) ADS-B is an air traffic control (ATC) system that uses signals from Global Positioning Satellites (GPS), instead of radar data, to keep aircraft at safe distances from one another. The ADS-B system provides air traffic controllers and pilots with accurate information that will help keep aircraft safely separated in the sky and on runways. With ADS-B some of the responsibility for keeping safe distances between aircraft is shifted from air traffic controllers on the ground to pilots who will have displays in the cockpits showing air traffic around them.
Conventional air traffic control systems require multiple communication links due to spectrum congestion at a single frequency, such as 1090 MHz. Conventional air traffic control systems include in addition to a link at 1090 a second link known as UAT (Universal Access Transceiver) at 978 MHz for use by General Aviation (GA) for air traffic data. Thus, GA is ‘incommunicado’ with commercial ATC, and does not show up on ATC displays. Since commercial and GA aircraft, and ATC systems, have a need to be aware of aircraft, the so-called dual-link configuration forms a part of the conventional FAA ADSB. It would be desirable to provide a system that overcomes the need for multiple communication links in air traffic control systems.